How to Build a Lava Moat (with xkcd)

How to Build a Lava Moat (with xkcd)


There are a lot of reasons for wanting a lava
moat around your house, but not that many how-to videos explaining how to build one. So we’re here to change that. It’s actually pretty easy to make lava,
at least in principle – the ingredients are just rocks and heat. Lots of heat. Most rocks melt at temperatures between 800
and 1200 celsius, which is hotter than your oven, so you’ll need a gas or charcoal powered
forge, or an electric furnace. It’s tempting to choose a kind of rock or
even metal or glass that melts at a lower temperature, but then it won’t glow as much:
the intensity and color of the glow depends on how hot the lava is, and you definitely
want a lava moat that glows (preferably a nice bright orange-yellow color). For this reason, we recommend only top quality
Keweenawan basalt obtained from the upper midwest. One of the challenges in maintaining a glowing
lava moat is that it’s literally radiating away its energy in the form of heat and light;
this means you can’t simply melt your lava, pour it into your moat, and call it a day. Your lava moat is going to need some kind
of built-in heating apparatus to make up for the losses: a ceramic crucible with high temperature
electric heating coils will work just fine. And you’ll definitely want a good layer
of insulation to keep heat from leaking into the ground – because you’re going to need
a lot of heat! At the temperatures we’re working with,
lava radiates roughly 100 kilowatts of heat per square meter (that’s equivalent to 1000
100-watt lightbulbs per square meter – though you can’t fit 1000 100-watt light bulbs
into a square meter, if that gives you any sense of how intense lava is). Anyway, electricity typically costs around
10 cents per kilowatt hour, so each square meter of lava moat is going to cost you around
$10 per hour. This means that a lava moat a meter wide and
enclosing an area roughly the size of a football field will cost $60,000 per day to keep running. If you don’t like the idea of being reliant
on somebody else to keep your lava moat home security system operational, you could instead
power it with solar panels, or build your own power plant. Each of these has its pros and cons: solar
power never needs fuel resupply shipments: the sun is going to keep burning for a while. However, every square meter of lava moat requires
2000 square meters of solar panels to keep it glowing day and night. We don’t need to explain the security risks
of putting your lava moat’s power source outside of the protection of the lava moat,
so if you want a lava moat a meter wide powered entirely by solar panels inside of the moat,
the math works out that the moat needs to surround an array of solar panels 8 kilometers
across. Which is clearly absurd. You can have a wider and yet more reasonable-sized
moat if you instead build your own commercial scale power plant inside it – coal and nuclear
power plants produce enough energy to heat a lava moat 10 meters wide and encircling
an area 500 meters across – enough space to fit the power plant and your house inside! The downside is that (unless you build your
moat on top of a coal or uranium deposit) you’ll need to bring in outside fuel, so
your lava moat won’t be entirely off-grid. Perhaps the best off-grid option for powering
your lava moat is simply to take inspiration from the source of lava itself: the earth’s
own internal heat. Assuming you don’t have access to an island
in a lava lake in an active volcano, the next best option is geothermal power: by choosing
the right location, a good geothermal power plant can heat a modest-sized lava moat that’s
perfect for protecting a single family home. I suppose you might also want to learn about
precisely how wide your lava moat should be to deter intruders, or how to cool your house
once it’s successfully encircled by lava, or how to deal with all the noxious fumes
given off by lava. And for that, you need to check out the full
lava moat instructions available in the book, “How To” by Randall Munroe, which this
video is based on (and supported by). How To is an absurd and entertaining self-help
guide full of ridiculous over-the-top advice about everything from how to dig a hole, to
how to be on time, to how to ski, to how to catch a drone. You can find a how-to guide for how to obtain
a copy of “How To” in the video description, and a big thanks to Randall and “How To”
for supporting and inspiring this “How To” video.

Comments

  1. Post
    Author
  2. Post
    Author
  3. Post
    Author
  4. Post
    Author
  5. Post
    Author
  6. Post
    Author
    Nate Underwood

    now all I am is one geothermal powerplant away from building my very own lava moat, if only I had a geothermal plant

  7. Post
    Author
  8. Post
    Author
  9. Post
    Author
  10. Post
    Author
    Brady DeGrands

    Could I use the lava to heat up water to turn a turbine to power the lava heater uppers and then use some alternate source to get the power needed to make up for the power lost in heat?

  11. Post
    Author
  12. Post
    Author
  13. Post
    Author
  14. Post
    Author
  15. Post
    Author
  16. Post
    Author
  17. Post
    Author
  18. Post
    Author
  19. Post
    Author
  20. Post
    Author
  21. Post
    Author
  22. Post
    Author
  23. Post
    Author
  24. Post
    Author
  25. Post
    Author
  26. Post
    Author
  27. Post
    Author
  28. Post
    Author
  29. Post
    Author
  30. Post
    Author
  31. Post
    Author
  32. Post
    Author
  33. Post
    Author
  34. Post
    Author
  35. Post
    Author
  36. Post
    Author
  37. Post
    Author
  38. Post
    Author
  39. Post
    Author
    Steve McQ

    You could use a bunch of fresnel lenses to heat up and melt the rock quite fast, a 50x50cm fresnel lens can melt steel in a few seconds.

  40. Post
    Author
  41. Post
    Author
  42. Post
    Author
  43. Post
    Author
  44. Post
    Author
    3131Bubba1313

    Why not have a natural gas power plant instead? Have your home built over a producing sweet gas well site and power your boilers from that. Plus the produced water can be filtered and fed as makeup water for your boiler.

  45. Post
    Author
  46. Post
    Author
  47. Post
    Author
    Am Cat

    Dig a ring (or square, I guess) around your house that is at least 5 blocks wide and 3 blocks deep, although personally I like to stretch these dimensions by a block or two. I'd recommend leaving at least 5 blocks between the ring and whatever building you put in the middle of it, so you can make a farm inside, space for other security measures, or just to walk around in. Then again, this is just a guide, do what you wish.

    Once that is done, take obsidian and line the inside of the ring with it. Don't worry, I already made space when I told you the size of the ring, no further digging required. When you finish that, go to the innermost layer of obsidian and continue it two or three blocks up. if you want, you could stretch the width of the ring beforehand to save space for a thicker inner wall (but make sure you save at least 3 blocks of width in the moat for the lava!), and even add an overhang to your wall for more difficult entry.

    Another option for your wall is instead of an overhang(or even with the overhang, for the craziest base), you can add cobwebs. If your enemies are scaling your wall and get stuck in the web, the only place they're going is down into the lava or away from the wall. If you want to get really high tech you can build an observer system that sets off an alarm, activates other security systems or notifies you in some way when the wall is tampered with.

    Now, it's time for the lava. All you need to do is fill the moat up enough that there is one unfilled layer at the top to hopefully trap invaders . So if you went with the ring I told you to make, there will be one layer of lava at the bottom. As I said before I usually make the moat a bit deeper. Also, I believe (at least in PE) lava will not damage cobwebs, so you could also put it over the lava for extra defence.

    Congratulations! You've locked yourself in your own high security base! Sure, you can build some stairs, but you'll need to get back in. There are so many things you can do. You can be as boring as those stairs, or as advanced as keycard reading slimeblock launchers. Secret entrances. Pop out stairs. Get creative! But that is all I have for you. I wish you good luck defending your home from those gosh darn creepers.

  48. Post
    Author
    Matthew Grimshaw

    Love Randall and XKCD. Hate Jeff Bezos and Amazon, who work to keep luxury in the hands of the wealthy while the poor die in the streets. In the future, please don't advertise for this monster or his companies. More details on his evil at the link below.

    https://youtu.be/3VRdyZgD3GI

  49. Post
    Author
  50. Post
    Author
  51. Post
    Author
  52. Post
    Author
  53. Post
    Author
    MauLob

    Just build your house inside a volcano. Done. You do not need to build OR maintain your lava moat.
    Added bonus – Your house would probably be on top of a mountain, making any attackers attack uphill.

    And if you're lucky, your home can give you even more free lava you could sell to others building their own lava moat.

  54. Post
    Author
  55. Post
    Author
    Chloe Clark

    hi Henry. i have misophonia and would greatly appreciate it if you took some measures before recording your voice to stop that 'smacking lips' noise. i love your videos but cannot listen to your voice any longer. the noise is unbearable.

  56. Post
    Author
  57. Post
    Author
  58. Post
    Author
  59. Post
    Author
  60. Post
    Author
  61. Post
    Author
  62. Post
    Author
  63. Post
    Author
  64. Post
    Author
  65. Post
    Author
  66. Post
    Author
  67. Post
    Author
  68. Post
    Author
  69. Post
    Author
    Christian Muller

    Wait. You forgot about building solar panels up instead of across like the football field. What if i have a Sky Scraper? I could make a Solar Christmas Tree and also build hella underground for geothermal if something goes bad with solar. Aka a plane or bazooka.

  70. Post
    Author
  71. Post
    Author
  72. Post
    Author
    JonnesTT

    Of course I'm going to build an old style atomic power plant which needs constant influx of water inside the boundaries of a lava moat. ^^
    8 square km is nit gonna be much saver than having no moat at all so just hire some armed guards, lava moats are for supervillains who own magic super-science machines

  73. Post
    Author
  74. Post
    Author
  75. Post
    Author
  76. Post
    Author
  77. Post
    Author
  78. Post
    Author
  79. Post
    Author
  80. Post
    Author
    Kilroy G

    ☆☆☆☆ I give this Four stars! This guide has helped me solve almost all of my trespasser issues and given the outer walls of my personal fortress a wonderful glow. Keeps out burglars and in-laws! Would have given it 5 stars but the heat from the lava moat boiled away the water for the moat holding the Laser Sharks.

  81. Post
    Author
  82. Post
    Author
  83. Post
    Author
  84. Post
    Author
    xSIO

    1. Dig a square moat at least 3 blocks wide.
    2. Fill enough buckets with lava to fill the entirety of your moat.
    3. Use the filled lava buckets to fill your moat.
    4. ???
    5. PROFIT!

  85. Post
    Author
  86. Post
    Author
  87. Post
    Author
  88. Post
    Author
    Percival de Rolo

    This. THIS is why I’m majoring in chemical engineering. This is why I’m struggling through thermodynamics rn. Thank you for giving my college journey a greater sense of purpose.

  89. Post
    Author
  90. Post
    Author
  91. Post
    Author
  92. Post
    Author
  93. Post
    Author
    IɴSɪmpʟeTermsJordaɴ

    1:09 "Now, you're probably wondering what I'm gonna need all this heat for. After all, I do build up heat for 12 hours."

  94. Post
    Author
    IɴSɪmpʟeTermsJordaɴ

    [lava moat must contain an area at least (π*(4/2)²)km² (or ~50km²) in order to be fully powered by an array of solar panels that would fit inside the area of the moat]
    @realDonaldTrump Okay so I know we've had our differences in the past but I have an idea to replace the border wall

  95. Post
    Author
  96. Post
    Author
  97. Post
    Author
  98. Post
    Author
  99. Post
    Author
  100. Post
    Author

Leave a Reply

Your email address will not be published. Required fields are marked *